package com.titaniume.forkjon;

import java.util.concurrent.ExecutionException;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.ForkJoinTask;
import java.util.concurrent.RecursiveTask;

/**
 * @ProjectName: juc
 * @Package: com.titaniume.forkjon
 * @ClassName: ForkJoinDemo
 * @Author: titan
 * @Description:
 * @Date: 2021/11/27 23:36
 * @Version: 1.0
 */


//1~100 拆分想加 类似二分查找
class MyTask extends RecursiveTask<Integer>{

    //拆分差值不能超过10 计算10以内的数量
    private static  final Integer VALUE =10;

    private int begin; //拆分开始之
    private int end; //查封结束值
    private int result; //返回结果


    //创建有参数的构造
    public  MyTask(int begin,int end){
        this.begin = begin;
        this.end = end;
    }



    //拆分合并过程
    @Override
    protected Integer compute() {
        //判断相加两个数值是否大于10
        if((end-begin)<=VALUE) {
            //相加操作
            for (int i = begin; i <=end; i++) {
                result = result+i;
            }
        } else {//进一步拆分
            //获取中间值
            int middle = (begin+end)/2;
            //拆分左边
            MyTask task01 = new MyTask(begin,middle);
            //拆分右边
            MyTask task02 = new MyTask(middle+1,end);
            //调用方法拆分
            task01.fork();
            task02.fork();
            //合并结果
            result = task01.join()+task02.join();
        }
        return result;
    }
}




public class ForkJoinDemo {
    public static void main(String[] args) throws ExecutionException, InterruptedException {
        //创建MyTask 对象
        MyTask task = new MyTask(0, 100);
        //创建一个分支合并池对象
        ForkJoinPool forkJoinPool = new ForkJoinPool();
        ForkJoinTask<Integer> forkJoinTask  = forkJoinPool.submit(task);

        //获取最终合并之后的结果
        Integer result = forkJoinTask.get();
        System.out.println(result);
        //关闭池对象
        forkJoinPool.shutdown();
    }
}
